Mixing diet drinks with alcohol makes you drunker

Vodka and seltzer. Rum and diet. Whiskey and water. These common cocktails served up with low- or no-calorie mixers get you drunker, faster than full-cal versions of the drinks, according to a new study -- and expose diet-cocktail drinkers to possible safety risks.

Dennis L. Thombs, PhD, of the University of North Texas Health Science Center, previously found that bar patrons who drink alcohol with diet drinks leave the bar more intoxicated than those consuming full-calorie drinks. A new study published in the journal Alcoholism: Clinical & and Experimental Research is the first to confirm Thombs' finding in a lab setting.

The study quantified lo-cal drinking's impact -- 18 percent higher blood alcohol levels. And in an interview this morning, one of the study's authors suggested why sugary drinks keep you more sober.

When you mix alcohol with regular soda, juice, or another mixer with sugar and calories, your body treats your drink more like food, according to researcher Cecile A. Marczinski, PhD, an assistant professor of psychology at Northern Kentucky University. The drink stays in your stomach longer, as a result, and the alcohol is absorbed into your bloodstream more slowly. When you drink alcohol with a diet mixer, the drink flows through your digestive system faster, allowing your small intestine to release more alcohol into your bloodstream.

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"Just as we've known for a long time that eating food with alcohol slows your body's absorption of alcohol, sugary drinks also appear to keep alcohol in the stomach longer, which is a good thing," Marczinski explains.

In the study, Marczinski and her team dosed participants with either vodka mixed with Squirt or diet Squirt. Researchers recorded the participants' blood alcohol content and asked them to rate their level of intoxication, fatigue, impairment, and willingness to drive. Although the subjects had higher blood alcohol levels after drinking the diet drinks, they did not think they were more intoxicated.

"What we found was, when people consumed the same amount of alcohol with a diet drink instead of regular, their [blood alcohol levels] were 18 percent higher," Marczinski said. "But I think probably nobody realizes that this is a concern, so awareness of this effect is the key thing."

Women should be especially aware of this effect, Marczinski says. They're more likely than men to order alcohol with diet drinks, and women are already more sensitive to the effects of alcohol. Marczinski's safe drinking tip? Alternate between alcoholic drinks and something non-alcoholic to both limit calorie consumption and keep intoxication levels in check.